message: fixing documentation

Fixes golang/go#26766

Change-Id: I43ad2deb0a55f2c18c820f7885fa9eee4b0e6cd4
Reviewed-on: https://go-review.googlesource.com/127551
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Iskander Sharipov <iskander.sharipov@intel.com>
Reviewed-by: roger peppe <rogpeppe@gmail.com>
diff --git a/message/doc.go b/message/doc.go
index b9584a2..72e8fde 100644
--- a/message/doc.go
+++ b/message/doc.go
@@ -17,7 +17,7 @@
 //    p.Printf("%d ducks in a row", 4331) // Prints 4,331 ducks in a row
 //
 //    p := message.NewPrinter(message.MatchLanguage("nl"))
-//    p.Println("Hoogte: %f meter", 1244.9) // Prints Hoogte: 1.244,9 meter
+//    p.Printf("Hoogte: %.1f meter", 1244.9) // Prints Hoogte: 1,244.9 meter
 //
 //    p := message.NewPrinter(message.MatchLanguage("bn"))
 //    p.Println(123456.78) // Prints ১,২৩,৪৫৬.৭৮